Machines with moving parts need predictive maintenance to lower production costs. As a part of Condition Based Maintenance (CBM), the timing and need for maintenance can be predicted with a condition monitoring system. Vibration sensing using accelerometers is the standard measurement for machine monitoring. These sensors measure vibration at the location where they are attached to the machine.
While accelerometers come in various forms, their basic principles remains the same—make physical contact with the machine being monitored and generate a signal that is proportional to the harmonic motion experienced at the point of contact. Permanently installed accelerometers are often attached to the machine with screws and wired connections. Besides their intrusive nature (designed while the machine is assembled), such sensors cannot be mounted on many moving parts, making it impossible to monitor “locations” that may be critical from a vibration standpoint.
Permanently mounted accelerometers are often complemented with handheld vibration monitoring equipment. However, signals generated from sensors mounted “far away” from a machine pick up background noises such as those generated by a helicopter body. This can obscure important signatures of failing gears or bearings. Further, it may not be safe to approach the machine with an attachable handheld sensor and try to make the sensor head reach the remote location of interest.